"In total 12 people were evacuated from the flats by the police, all of them were adults.

"Three flats have been left uninhabitable following the fire.

"At this stage we do not know if smoke alarms were fitted in these properties,but we would like to remind members of the public that it is absolutely critical that people have working smoke alarms fitted in their properties.

"The fire service will fit these free of charge."

Crews spent around an hour bringing the fire under control and remain at the scene today to begin investigation work into the cause.

The police officers have since been discharged from hospital. One woman remains in hospital as a precautionary measure.

A spokesman for Preston police said in a post to Twitter: "During the night we have responded to a substantial flat fire just outside our Police Station.